A thin layer of magnesium fluoride (n = 1.38) is used to coat a flint-glass lens (n = 1.

5. A thin layer of magnesium fluoride (n = 1.38) is used to coat a flint-glass lens (n = 1.61). What minimum thickness should the magnesium fluoride film have if the reflection of 667 nm light is to be suppressed? Assume that the light is incident at right angles to the film. in nm